SQL 查询返回记录数，用于两列的唯一组合

Question

I am looking to count how many routes each code has per week. This would mean I want to find how many routes there are for each combination of code and year_of_week. I have a set of data as follows:

Data:
Code    Year_and_Week   Route
1       201501          A
1       201501          B
1       201523          C
1       201633          A
1       201633          A           
1       201643          A
1       201643          B
1       201643          C
1       201643          D
2       201503          A
2       201503          C
2       201520          A
2       201624          B           
2       201624          B
3       201643          A
3       201643          C
3       201643          D

I have a code snippet that works to retreive my desired result, but only when I input a "Where code= #" line in the code. I want the results to output for each code type.

Select Year_and_Week, Count(Route)
From Deliveries
Where Code=1
Group BY Year_and_Week

Desired Output:

Code    Year_and_Week   Route_Count
1       201501          2
1       201523          1
1       201633          2           
1       201643          4
2       201503          2
2       201520          1
2       201624          2
3       201643          3

I am trying to get this output so that I can then take a maximum and minimum of Route_Count for each code for analysis purposes using a CTE like...

With Route_Number_CTE (Year_and_Week, Route_Count) As(
Select Year_And_Week, Count(Route)
From Deliveries
Where Code=1
Group BY Year_and_Week
)

select min(Route_Count),max(Route_Count)
From Route_Number_CTE;

Answer 1

Just add code to the select and group by clauses:

select code, year_and_week, count(route) no_routes
from deliveries
group by code, year_and_week

Note that count(route) counts only non- null values of route . If this column is not nullable (or if you want to take in account null values), this is simpler and more efficiently written:

select code, year_and_week, count(*) no_routes
from deliveries
group by code, year_and_week